It has heretofore been proposed that a plastic closure be used on the threaded open neck of a container such as a bottle to provide a seal for carbonated beverages. One of the basic problems is the limited sealing area on the open end of the neck which is engaged by the closure.
It has heretofore been suggested that plastic closures be formed that deflect or reshape a liner into sealing engagement with the neck of the container. Typical arrangements are shown in U.S. Pat. Nos. 4,351,443, 4,381,840 and PCT Patent Document No. 82/02181. U.S. Pat. No. 4,351,443 shows an arrangement which relies on the configuration previously formed on the base wall of the closure for deflecting the liner against the inside surface of the neck or the outside surface of the neck. U.S. Pat. No. 4,381,840 shows an arrangement wherein projections on the inner surface of the base wall of the closure compress the liner against the free end of the finish. PCT Patent Document No. 82/02181 shows an internal bead at the inside corner of the closure for reforming the liner around the corner radius of the finish. Such arrangements are more difficult to make. In addition, such arrangements often do not accommodate variations in the bottle finish diameter.
Accordingly, among the objectives of the present invention are to provide a carbonated beverage package which has improved sealing characteristics; which provides such characteristics at minimal cost, and which can be readily manufactured, and which accommodate variations in the container or bottle finish diameter.
In accordance with the invention, a carbonated beverage package embodying the invention comprises a bottle having a neck with an external thread and a closure comprising a base wall and a peripheral skirt having an internal thread interengaging the thread on the neck. A flexible liner is interposed between the interior surface of the base wall of the closure and the open end of the neck. The closure is made of plastic and includes a portion at the juncture of the base wall and peripheral skirt which is axially deformable relative to the remainder of the base wall to a permanent shape such that when the closure is applied to the neck and the closure is rotated by relative rotation between the closure and the neck while simultaneously an axial force is applied to the deformable portion of the cap, the deformable portion is displaced axially relative to the base wall to a permanent shape causing the liner to be deflected about a portion of the outer surface of the neck adjacent the open end of the neck thereby increasing the contact of the liner with the neck.